Making a glider is difficult but not impossible look up Otto Lilienthal he built many in the 1880's&90's but the problem is using them as the poster suggests. Lilienthal after years of work study and experiment produced hang-gliders that could lift a man, say 10m wingspan made from wood and canvas weighing only 25kg. These fell at about 10m/s in still air so you need a bigger updraft than that to gain altitude.

Without aluminium or carbon fibre that is about as good as it can get and without polyester fabric it is vulnerable to tears. Fragile and with a low lift to drag ratio the result is impressive but not really useful. He seems to have managed a glide ratio of about 5. (a seagull is 15-40) The first true hang gliders took until the 1960's and it took until the 1980's to reach modern glide ratios of 14

As I said earlier the physics are brutal. A flying man is right on the edge of what is achievable.

To be useful a device must be buildable, transportable, launchable, recoverable and reusable reliably enough to be worth using in addition to actually getting high enough to do something useful and keep its pilot alive often enough to be worth it.

I can't see it working and if it did only the most powerful kings would be able to support a glider corps (the support staff would be huge!) so no nomads or desert raiders with gliders and only a suicidal pilot would try to operate from a sailing ship!

Now the easy way is to cheat, either don't explain how it works or say each pilot wears a jacket of cavorite.
 
Lilienthal after years of work study and experiment produced hang-gliders that could lift a man, say 10m wingspan made from wood and canvas weighing only 25kg. These fell at about 10m/s in still air so you need a bigger updraft than that to gain altitude.
This is excellent information. Thank you. Ibn Firnas might have even been able to do a little better, since I gave him silk instead of canvas, but it's nice to know that a glide ratio of 5 is reasonable. I would have been happy with 2!

I'm not married to the Saharan Glider Culture. Perhaps gliding is so expensive that only royal organizations can do it. That works too.
 
So now that we've established that in 867, Abbas ibn Firnas successfully launched himself from the minaret of the Great Mosque of Cordoba and flew it to a smaller mosque about 800 meters away, achieving a glide ratio of 4.

Let's say that incremental improvements give us a mean glide ratio of 5 for gliders through the 9th and 10th centuries. How does that change things?

I propose that the Umayyads set up a messenger service using gliders, which hopped from one mosque's minarets to another's (with many way-towers built along roads). This allowed them to maintain tighter control over greater distances, and brought about the Caliphate of Cordoba earlier than in OTL. By the 910s, the Caliphate of Cordoba extends into North Africa (following the Vendavel winds) and Catalonia (following the Mistral). Gliders gave Umayyad armies an advantage in intelligence, and helped greatly in conquering territory in the Pyrenees.

The Umayyads only stopped at Barcelona because they focused more attention on the Mediterranean coast of Africa before they fell in a civil war that came a generation earlier than OTL -- in the 970s.

Meanwhile, they have gliders now in Galicia, Toulouse, and Egypt...

How does that sound for a first step?
 
Ok I have been trying to avoid this but let’s talk numbers:

A glide ratio of 5 sounds good but think what that means.

The highest building in the world for 4000 years was the great pyramid, say 150m high. So you haul your fragile 10m wide craft to the top, strap yourself in and jump off.

In still air you would travel about 750m say about half a mile or a gentle 10 minute stroll.

Now the statistic related to glide ratio is drop rate here that is 10m/s that means you travel that distance at an impressive speed just over 100 miles per hour (minus a bit because you will slow down to land!) but you have less than 15 seconds of flight.

Now in the 1980’s my (frankly cheap and hired) hang glider could achieve a glide ratio of about 15 so in the same conditions, I could travel three times as far (2,250 m ) or about ½ hour walk back.


The issue is trigonometry which means if you double the glide ratio the drop rate falls by a factor of about 4. So my flight would be at about 25 miles per hour and I would fall at just over 1m/s.


So my flight would last about 2 & 1/2 minutes. That is 2.5 minutes to look around, spot a thermal, steer the craft, observe the area and pick a landing site (it feels much longer).


In addition the slower fall means thermals and updraft are much more effective which explains why distance records in the 1980’s went from meters to hundreds of miles.


A modern hang glider can achieve better up to about 20 glide ratio and in a light breeze over a slight hill will just stand in the air.


Even so modern hang gliders do not just take off just anywhere they go to a high steep hill with a deep valley facing into the wind on a day when thermals are likely or they get hauled into the sky by a very long wire on a fast winch or by a light aircraft.


And that is why any attempt to make this plausible will crash and burn the closer you examine it.


I seriously suggest you throw reality out of the window, I want to see the Sicilian Arab lady glider squadron defending the pope in Rome from the French king, I want to see the brave defenders of Gibraltar sending a young boy across to Africa to get help, I want to see a Mongol invasion defeated by Berber tribesmen sweeping out of the Sun to capture the Khan.
 
I'm pretty surprised that this thread does not seem to mention the fact that you can launch a glider from a flat surface by using land motion, a towing cable and favorable wind.

Because, after all, that's how you launch a toy kite!

Now you'll say it's another thing to launch a glider able to carry a man.

Well, no, it's not different, and Sir Cayley proved it in 1853. If you have a couple of well-trained horses, a straight road headed into the direction of the prevailing winds, a good windy day, a well-designed glider, possibly with a detachable takeoff wheeled trolley, a towing cable and finally a thermal to pick it up after take off (Sir Cayley's coachman crash-landed after just 300 meters...)... you're gold even if you build no minaret launchpad.

I've written something on these topics myself:
http://www.warehouse23.com/products/SJG37-2639
 
I'm pretty surprised that this thread does not seem to mention the fact that you can launch a glider from a flat surface by using land motion, a towing cable and favorable wind.

Because, after all, that's how you launch a toy kite!

Now you'll say it's another thing to launch a glider able to carry a man.

Well, no, it's not different, and Sir Cayley proved it in 1853. If you have a couple of well-trained horses, a straight road headed into the direction of the prevailing winds, a good windy day, a well-designed glider, possibly with a detachable takeoff wheeled trolley, a towing cable and finally a thermal to pick it up after take off (Sir Cayley's coachman crash-landed after just 300 meters...)... you're gold even if you build no minaret launchpad.

I've written something on these topics myself:
http://www.warehouse23.com/products/SJG37-2639

Well you can but without modern materials and a high speed winch there are a lot of issues.
First a good glider is a poor kite and visa versa and if you try with a wooden hang glider I suspect it is likely to fall apart.

So I would use two kites and a glider, first use a smaller kite to prelift the rope and then use a strong man-weight travelling kite to lift the glider to the end of the string at which point you cut the string and fly away.

How high you get depends on the wind strength too weak and you stay on the ground too strong and the whole thing falls apart mid air.

I know little of man-lift kites but the interweb gives a wind speed of 18-25 miles an hour for a modern kite 10m across lifting 85kg. I suspect ancient materials would need more lift and break apart more easily and do not forget the weight of the rope (say 1kg/10m).

In other words not very practical.

My solution is to invent the hot air balloon and hang a glider under it. That lets you get many hundreds of metres in the air giving you reasonable flight times and distances and low wind speeds would be kind to fragile wings. But it is not very mobile and not quite the image you were aiming for.
 
Ok I have been trying to avoid this but let’s talk numbers:
Please don't hesitate to talk numbers! I like them :)

I agree though, there will be the need for some suspension of disbelief, and I do plan to gloss over the details of exactly how badly the first gliders worked. That won't be hard since the story I'm writing takes place more than a thousand years after ibn Firnas's invention.

I really appreciate all your help, though, getting as close as possible to plausibility.
 
Now, to putting all cerebus's and Michele's ideas in one place for a Timeline of Glider Development

850-950

Gliders used for spectacle to praise their source of funding (Amirs)

Use: religious purposes

Use: delivering messages

Infrastructure improvements like way-towers and the use counterweight elevators to get them to the top

950-1050

Use: aerial reconnaissance

Use: land-surveying

Infrastructure: updraft-ramparts

New Technique: two-kite-assisted takeoff

1050-1150

Technique: horse-cart-assisted takeoff

Infrastructure: runways

New Design: Chanute glider

Use: insertion of spies and assassins

1150-1250

Materials improvement: angouma wood

Technique: indirect ballista-assisted takeoff (in which an object is launched to which is tied the glider)

1250-1350

Material: bamboo

Design: paraglider

Use: aerial bombardment

Technique: balloon-assisted takeoff

Technique: direct ballista-assisted takeoff

Technique: horse-back-assisted takeoff (too crazy?)

1350-1450

Technique: rocket-assisted takeoff

Use: bombing

1450-1550

Use: exploration and mapping

Use: air-defense

1550-1650

Materials: sitka spruce

1650-1750

Design: armchair glider

Use: transportation and colonization

1750-
Modern age follows with plastics and internal combustion

As always, I am happy to drop or add anything.
 
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Scene 1
Also, I finished the first scene in my story this week. Cerebus, do you have any advice for making the act of gliding more realistic?

The last echoes of the call to worship fade into the heat rising off Cordoba, and against Tariq’s back the glider shivers.

A voice in his headset, "Go with God, as they say."

Tariq ibn Fortun al-Muley refocuses his attention from the red roofs spread before him to the drone perched on the railing, here at the top of the minaret. "Well, you're going with me, anyway."

The drone operator coughs in his Vinland call center. "Whoa, there, buster. That is the sort of casual blasphemy that I will not tolerate on one of my shoots."

"Leif," says Tariq, "you're a big, fat Vinlander and you worship nothing but money."

"Money given to us by viewers, some of whom will take offense at your godless, libertine, bleeding-heart, naive, irritating – "

"When are we going live?"

"Thirty seconds ago."

"Fuck you, Leif."

Leif coughs again, which is the closest the dried-up old cynic can come to laughter. "90 seconds."

Tariq closes his eyes. He flexes his toes, thinking about the blocks of stone stacked between him and the ground. The tug and creak of silk, leather, and cypress wood at his back. The sleepy cooing of the pidgeons.

Abbas ibn Firnas might have felt the same grit against his shoes and the load on his shoulders. Smelled the same stone dust, the bird guano, the ancestors of these same orange trees. Not the car exhaust, though, or the sound of the drone's rotors as the flying camera takes up position in the air. He breathes.

"Action," whispers Leif, and Tariq jumps.

They've already recorded the narration for this shot. "My route retraces that of the explorers of old, the men and women who pushed the boundaries of human experience, trade, culture, and war. From the minaret of the Great Mosque of Cordoba to the Forbidden City, follow me..." and on and on.

Tariq has already recorded all his lines. Gladhanded all the executives on four continents. Made sure the bribes were paid. Endured the stupid questions and the posturing by self-satisfied so-called intellectuals. All the bullshit you have to wade through to get done any good in this world.

Now all that remains is to miss the ground.

Tariq doesn't open his eyes until the wind catches him.

"Abbas ibn Firnas," his narration went, "made history in 236 when he leaped from the minaret of the Great Mosque of Cordoba, the dream of flight in his heart and a fortune in silk strapped to his back."

"And today," Leif joked during their last recording session. "It's a Fortun strapped to a piece of shit. Because your name is ibn Fortun," he explained unnessiarily, "and your historically accurate glider is a piece of shit."

Leif was right. The cedar-and-silk triangle creaks and shudders over Tariq, clawing a swath of turbulence down the air. It moves only a little more horizontally than it does vertically, and it slews to the right, but it doesn't quite drop Tariq.

He doesn't think it will. Tariq had tested the glider on incline takeoffs, but it's one thing to skip down a hill and another to fling yourself of a historical monument. Leifs jokes about making snuff films didn't helped.

"This wasn't ibn Firnas's first jump," Tariq mentally reviews the recording he made yesterday. "He'd tried it before in 253, wearing wings made of wood and feathers. He nearly killed himself in the attempt. But he didn't give up. He ransacked the libraries of Al-Andalus looking for help with his dream. He found it in China.

"Kites had been flown in the Middle Kingdom for centuries even then – triangular constructions of silk and bamboo. Abbas didn't know what bamboo was – the writings of Mu'min ibn Said suggest Abbas experimented with cattail reeds – but he did manage to find silk. Enough silk to build Europe's first glider."

Tariq wrestles his replica through the air, trying to look good for Leif's camera, trying to get his own small helmet-mounted camera pointed at the buildings and cars and watching pedestrians.

"And that is the power of multiculturalism," went the narration. "The alchemy of Chinese lore, Arab cleverness, Berber bravery, Andalusian spirit. The mixture greater than the sum of its parts, bearing us all aloft."

They will have to listen now. Tariq will leverage his bravery and ingenuity into a platform he can use, or else this whole life-threatening stunt will be in vain.

A swift shoots past him, effortlessly twisting through his slipstream in search of nothing nobler than breakfast.

Tariq wonders if he has time for the 'you can't see borders from up here' bit, but no. The minaret of the Roman Wall Mosque is coming up on his left.

He leans sideways, fighting the glider...straight ahead...no on his left again...and now Tariq has lost quite a lot of altitude.

The minaret is a lost cause and the dome of the mosque is probably a bad idea. The street in front is already busy with morning traffic and worshipers, but the alley on the side of the building is empty.

Tariq sways back and forth, slaloming like an alpine skier, shedding speed and altitude.

He kicks off the roof of the building next to the mosque – a Vinland Porridge Hut – and slants down toward a wall of whitewashed brick. There he kicks himself vertical, dumps the air out of his glider, and falls ten feet to the pavement. Pigeons and cats scatter, and while he misses the overfull dumpsters standing in the alley. Tariq splashes into the puddle of foul water they have leaked.

The drone buzzes into the alley as Tariq straightens, wincing from the pain his his legs as well as the smell.

"I think I managed that a little more elegantly than Ab – "

Tariq's line is interrupted by an old woman shouting around the corner. "You kids get out of there. Little morons. Playing in garbage water."

Tariq straightens the glider across his shoulders and walks out of the alley.

"Aha," says the woman when she sees him. "A big moron."
 
It is 30 Years since I jumped from a hill and went up!
But if nobody better is available.
1. I really like this ( although porridge hut is a cheap shot)
2. He probably will find there is no time to think but that is a nessesary weasel
3. I suspect if he drops the last ten feet he will break both ankles at least. Try three feet
4. Would feet be a measurement or would it be something like a qasaba high?
 
Thank you very much :)

>>although porridge hut is a cheap shot<<
Haha. Okay :) I'll replace it with something better. I'd like it to be foreign fast food of some sort, and I was thinking that "porridge" (corn meal mixed with meat broth) is a popular export from North America. Other possibilities are Lamb-In-A-Sack from the Mongol sphere and Pickle-Fish from Northern Europe. Other goofy ideas?

>>2. He probably will find there is no time to think but that is a nessesary weasel<<
Hm. I need to think about that one. I think I can make it work, since all the stuff he's "saying" during his flight is actually narration that he previously recorded and plans to have played over footage of the flight.

>>Would feet be a measurement or would it be something like a qasaba high?<<
I wanted to use OTL English translations of the Andalusian Arabic Tariq actually speaks, but now I realize by that rule I ought to say "when he jumped from the tower in 877" (CE) instead of 263 (AH). What do you think?
 
Scene 2
So, in my next scene I'm planning to have Tariq glide on increasingly sophisticated gliders along the old way-towers from Cordoba to Gibraltar, narrating along the way about the first hundred years after ibn Firnas's discovery.

As per cerebus's recommendation, I'm planning on saying that gliders were originally used for spectacles in praise of their patrons. But there was also growing demand for gliders for purposes religious and practical (message delivery). Higher demand for silk lead to better-established trade routes with Arabia, which lead to slightly lower silk prices. When silk prices refused to fall further, Andalusians turned to alternatives such as flax (produced locally), jute (food-quality obtained from Egypt, fiber-quality from India), and hemp (from the Middle East), with efforts to improve trade and grow these plants (plus silk) locally. The Caliphate of Cordoba covered all but the northern fringe of Iberia, and the entire northern coast of Africa, while trade routes to stabilized politics from Gibraltar to the Indus for a century. The Caliphate collapsed in 980 when Al-Hakam II died of plague (introduced into Iberia by gliders).

During this time, we get the spread of way-towers and updraft-ramps, as well as the first counterweight elevators.

How does that sound?
 
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Nice, completely impossible of course but who cares☺ Finding a hill is better than building a tower but Towers are cool.
I was thinking, would an Islamic invented media use human images (ie tv) or would it stick to voice radio? Perhaps images of places but not people would be allowed?
 
Thank you very much :)

>>although porridge hut is a cheap shot<<
Haha. Other goofy ideas?

>>porridge palace? Slice and Sizzle? Tripe and Trotter?<<



>>Would feet be a measurement or would it be something like a qasaba high?<<
I wanted to use OTL English translations of the Andalusian Arabic Tariq actually speaks, but now I realize by that rule I ought to say "when he jumped from the tower in 877" (CE) instead of 263 (AH). What do you think?
I think you should use what sounds best. You can not really reproduce an imaginary language from a never was world so do what you feel is best.
personally I find measurements and currency anoying but that is a matter of taste.
 
Nice, completely impossible of course but who cares☺ Finding a hill is better than building a tower but Towers are cool.
I was thinking, would an Islamic invented media use human images (ie tv) or would it stick to voice radio? Perhaps images of places but not people would be allowed?

Even modern Salafi Muslims are divided as to whether TV is acceptable, so I don't see why it wouldn't be used. Not to mention it isn't like every Muslim country has strictly followed Sharia enough to ban even the creation of television. Look at the rich tradition of Islamic instrumental music, which is definitely haram according to strict interpretations.
 
>>Finding a hill is better than building a tower but Towers are cool.<<
So I suppose hilly country will be more strategically important ITTL?

>>You can not really reproduce an imaginary language from a never was world so do what you feel is best.<<
I would like to find someone who speaks Moroccan or Tunisian Arabic and see if they can give me some nice turns of phrase. But yeah.

>>Even modern Salafi Muslims are divided as to whether TV is acceptable, so I don't see why it wouldn't be used.<<
It's a plot-point that they do use TV with visuals, so.
But I do need to think more about how The Union of Mediterranean Taifas' culture and society are different from those of the (roughly equivalently wealthy and high-tech) European Union.

Thanks! More tomorrow :)
 
Scene 3
Well, sorry. It turns out I'm not allowed to post any more of the text of The Goose's Wing (although contact me privately if you want to beta-read it)
But I can summarize and world-build, so here goes.

Tariq's next stop is Shamsa (near OTL Cairo), where he talks about the 11th-century successors to the Caliphate of Cordoba: the Divisions in the west (plus some Berber and Christian kingdoms) and the Mustwad Caliphate in the east, descended from a sect of glider-worshiping Berbers, based in Shamsa ("The City of the Sun") near OTL Cairo. The Mustwards end up being conquered by the Kurdish Shakkoyids in the early 13th century before the Mongols roll into town. There's also the expansion of a Takrur Empire in west Africa, feeding a northern demand for okoumé wood, and a nice little renaissance centered on Bologna in the 12th century, with paper, silk, gliders, and the Greek classics entering western Christendom. New technologies include horse-cart-assisted takeoff, runways, and Chanute (biplane) gliders.
 
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Scene 4
The next big event is the Mongol invasion, which starts out more or less the same as in OTL. Initially, things go a little better for China, but then the Mongols snap up silk route glider engineers and put them to work. They standardize designs and wed innovations to each other, and end up with even more of an advantage than they had in OTL. They penetrate farther into the Himalayas and southeast Asia, and much farther into Europe and Africa, pushing other people in front of them.

When the dust settles, Europe is (from north to south, west to east)

The Pomorian confederation (Iceland, Scotland, eastern England, western Scandinavia)

The Divisions (Iberia and North Africa) with more French, Berbers, and Kurds than you'd expect.

A broken France, now a mash of squabbling German and Magyar despots.
Sweden likewise full of Finns.
Balts, Estonians, Karelians, Northern Slavs in OTL Germany
Northern Poland and Baltic invaded by North Slavs, Tatars, Chuvash
East Slavs, Mongols, Tatars, Cumans in OTL Hungary and southern Poland

Area around OTL Moscow invaded by Tatars, Chuvash, Bashkirs

Ulus of Jochi (Central Asia and Eastern Europe: capitol Kiev) speaking Mongolian, Tatar, East Slavic, Udmurt, Kipchak, Bulgar, Cuman, Uyghur, Bashkir

Ulus of Hulagu (Middle East and the Balkans: Capitol Constantinople) speaking Mongolian, Tatar, Greek, Persian, Arabic, Kurdish, Seljuk, Bulgarian, Serbo-Croatian, Albanian

Ulus of Kitbuqa (Levant and eastern North-Africa: Capitol Shamsa (OTL Cairo))
Speaking Mongol, Seljuk, Arabic, Kurdish

The new Mongol rulers of half of Europe and North Africa are originally a mixture of Nestorian Christian, Tengri-worshipper, and Muslim. The two southern hordes quickly adopt Islam, while the northern Ulus of Jochi evolves a more standardized version of Tengriism, in which the Khan has been "lifted into the Wide Blue Sky, casting beneficent shade over all his people."

Tune in next time for: The Black Death!
 
You're really exaggerating population movements. The Mongols weren't a kill all, burn all, loot all horde smashing everything in their path and bulldozing the rest. They weren't capable of driving long-established civilisations and cultures into other civilisations and cultures. Cultures which did migrate in the face of the Mongols were mostly nomadic and definitely not established states like the Russians, Germans, Hungarians, etc. Sure, a lot of people would die, but the only place where cultures might have a chance at shifting permanently is Hungary, thanks to the highly favourable terrain for nomadic empires. And it would probably shift to a Cuman or Tatar state (or both?). Nomads can conquer Europe, but most of it just isn't good terrain to settling in.

Even the Finns and Estonians would be unlikely to migrate in the face of the Mongol hordes. They'd just melt into the forests and give the Mongols whatever they wanted while a Mongol governor ruled from Turku/Tallinn/wherever in place of a Swedish or German one.

Also, Kitbuqa wasn't a Borjigin descended from Genghis Khan, so if he or descendents had their own state, they'd be rebels against the Ilkhanate and would probably claim a different title (Sultan/King of Egypt).
 
But the Russians were displaced by the Mongols. They migrated north out of Kiev, and some of them settled in Moscow.

My thinking is that gliders both made it easier for conquering armies to penetrate forest and mountain strongholds, and allowed between communication between central authorities and outlying provinces. So the Mongol polities went farther, lasted longer, and resettled their new territories more permanently. In OTL, the most western Mongolic-speaking settlement is the Crimean Tatars (uh...right?). ITTL, they settle as west as far as the Upper Danube, pushing Hungarian, German, and Central Slavic people into France and the Alps. Maybe I got the details wrong, but what do you think of the general picture.

I need to think more about Scandinavia and ITTL northern Russia. My assumption has been that that area gets conquered by a nominally Mongol but primarily Volga Bulgar and Kipchak horde, which settles and assimilates into a Uralic culture. By the modern day, *Moscow is home to a Tengriist, Komi-speaking culture.

Kitbuqa is a rebel! I love it! As a Nestorian, he declares himself the ruler of the Presbyterate of Egypt!

I'll incorporate those details into the next chapter of the timeline, the post-Black-Death renaissance...
 
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